fixed bug 3428290 in sf.net, in DFM, if no hfi or net, output the error with usage

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@10943 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

perl-xCAT/xCAT/FSPbootseq.pm

@@ -34,9 +34,9 @@ sub parse_args {
     # Process command-line arguments
     #############################################
     if ( !defined( $args )) {
-        $request->{method} = $cmd;
-        return( \%opt );
+        return(usage( "Missing command with rbootseq in DFM, net or hfi ?" ));
     }
+
     #############################################
     # Checks case in GetOptions, allows opts
     # to be grouped (e.g. -vx), and terminates